Need Help With PLC's Assignment

Here We Go. I have been asked to produce a program using GX Developer. The PLC i have to use is a Mitsubishi FX1N(C). I have to produce a program which will control a temperature sensitive fan heater in a hallway which leads to 2 adjacent rooms. The Heater and fan are designed to operate under the following conditions:

Input the temperature from the two rooms in degrees celsius.

Find the average temperature between both rooms

Contert the temperature into degrees fahrenheit

Compare the temperature to a preset value of 72 (+ or - 2.75%) so basically 70 - 74

If the temperature is below 70 degrees F, then the fan and heater will operate and a 1.5 second flashing alarm will be energised until the temperature is increased to its pre-set value.

If the temperature is above 74 degrees F, then the fan will operate and a 1 second flashing alarm will be energised until the temperature is increased to its pre-set value.

If the temperature is between 70 and 74 degrees F then the fan and heater should be switched off.

In addition, count the number of time the temperature has been outside of the pre-set range in a 2 hour (use 20 secs for this example). Indicate this ammount using BCD on the output display LED's
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I have already started this program but was unable to finish and i dont own a PLC or a copy of GX Developer at home and I no longer have any lesson time on this. I know it is abit too much to ask but try and think of it as a challenge or a brainteaser. Heres what i have so far i have no idea if this is right or wrong: http://i63.photobucket.com/albums/h137/chriswall89/PLCsAssignment.jpg
excuse the quality of this picture. I had to make the quality lower in order to upload the picture. If you need this then i will gladly email. If anyone does help either send me the file via email or post a picture of the ladder diagram please. Thanks in advance to anyone who helps or tries to help.

Ok sorry. Its not that im lazy and im asking other people to do this for me, I would love to do it myself if i had GX developer and a PLC because the only way to learn this is to try it yourself. But i have tried obviously to come up with the program but i cant tell where i am wrong or right without a PLC. If someone owns a PLC could they please try tell me where I am right, where I'm wrong and what else i need to do in order to finish the program.
Or better still does anyone know if i could get a virtual PLC on the computer and where to get 1 please. I reckon i could probably find a copy of GX Developer somewhere myself. Thanks In Advance.